D2D technologies allow direct communication between terminal devices, and therefore, frequency spectrum efficiency of a cellular communication system may be effectively improved, transmit power of a terminal is reduced, and a problem of lack of frequency spectrum resources of a wireless communication system may be solved to some extent. The D2D mode has been accepted by the 3GPP standards organizations, is applied to a long term evolution (LET) communication system, and has a very broad application prospect.
In a D2D application scenario at least partially covered by a cellular network, in the case where a D2D device uses a dedicated channel, communication in the cellular network will not be interfered. However, when the density of users in a cell is high, the D2D communication will share or reuse frequency resources of cellular users. When the D2D communication and cellular communication reuse the same wireless resource, mutual interference will occur. By controlling the transmit power of a D2D signal, the interference of the D2D communication to the co-frequency cellular communication can be reduced.